will have or would have


We use the perfective will have when we are looking back from a point in time when something will have happened.

By the end of the decade scientists will have discovered a cure for influenza.
I will phone at six o’clock. He will have got home by then.

or looking "back" from the present:

Look at the time. The match will have started.
It’s half past five. Dad will have finished work.

We use would have as the past tense form of will have:

I phoned at six o’clock. I knew he would have got home by then.
It was half past five. Dad would have finished work.

We use would have in past conditionals to talk about something that did not happen:

If it had been a little warmer we would have gone for a swim.
He would have been very angry if he had seen you.



He was proclaimed (as the) king in 2009; without that he would have been crown prince.
What better way is to express the above sentence for it refers to the past action and would have continued to be true in the present.
May I use '' with out that he'll have been crown prince" ?

Thanks for your time.

Hello Andhrite,

I think the best formulation would be:

'...without that he would still be crown prince (today).'

We use 'would' for present meaning as we are talking about a hypothetical/imagined/not real present (as he was in fact proclaimed king).

Best wishes,



The LearnEnglish Team

Can't 'would' be used in less definitive sentences. Like "They are married for two years. They'd even be having a child". (usage of 'might' would sound like guessing)

Hello everyone,I am a bit confused about how to use WOULD in the following situation.If i am expecting a mail from someone and if I talk to myself about it, would it be appropriate to say "would he have replied to my mail ? " OR should I say "may he have replied to my mail ? "

Hi retriever,

I think what you should say is 'Will he have replied to my email?'. Although your use of 'may' is grammatically correct in the second question, 'may' is not generally used in questions that talk about the chance of something happening. Personally, I would probably say 'I wonder if he's replied to my email?', but your first question with 'will have' is grammatically correct.

By the way, 'mail' is an uncount noun and refers only to the kind of mail that is printed on paper; 'email' can be count or uncount and refers to the other kind that is more common nowadays.

Best wishes,
The LearnEnglish Team

'He will not have replied to the mail' sounds too definitive. Can we use 'He wouldn't have replied to the mail' to make it slightly probabilistic? If not could you please tell what are the other ways to say the same sentence

Hello Kirk

Thank you very much for your help.So even if 'would he have replied to my email ?' is grammaticaly correct, it cannot be used in such situations.One more thing, what is the difference between these two sentences:

(1)What would happen if I pressed this button?

(2)What will happen if I press this button?

To me both these sentences mean the same thing.

Hello ,, is it correct if I said " if you were my daughter I would've tickled your tummy until you wake up " and thanks :)